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PubMed1995

Relationship of cytochrome P450 activity to Clara cell cytotoxicity. IV. Metabolism of naphthalene and naphthalene oxide in microdissected airways from mice, rats, and hamsters.

Parenteral administration of naphthalene produces a dose-dependent and tissue-, species-, and cell-selective lesion of murine Clara cells. The rate and stereoselectivity of naphthalene metabolism by microsomal preparations correlate with tissue and species differences in cytotoxicity. Because earlier studies used microsomes obtained from whole tissue, differences in susceptibility of proximal and distal airways could not be related to differences in the metabolic activation or detoxication of naphthalene. Specific subcompartments of the respiratory system, obtained by microdissection, have been used to study the cytochrome P450-dependent metabolism of naphthalene and the epoxide hydrolase/glutathione transferase-dependent metabolism of naphthalene oxide. The rates of naphthalene metabolism were substantially higher in mouse airways than in comparable airways of hamsters or rats. Rates of metabolism were higher in distal airways than in the trachea of all species studied. Metabolism in mouse airways was highly stereoselective, whereas that in hamster and rat tissues was not. Nonciliated cells at all airway levels in mice were heavily labeled with an antibody to cytochrome P450 2F2; little labeling was observed in any portion of rat and hamster lungs. Postmitochondrial supernatants prepared from mouse and hamster airways metabolized racemic naphthalene oxide to diol and glutathione adducts at substantially higher rates than did comparable preparations from rats. Although glutathione levels varied 2-4-fold at different airway levels in the three species studied, levels at the most susceptible site (mouse distal bronchioles) were as high as or higher than those at other, less susceptible, sites. These studies support the view that the rate and stereoselectivity of naphthalene metabolism to naphthalene 1R,2S-oxide catalyzed by cytochrome P450 2F2 are critical determinants in the species-specific and region-selective cytotoxicity of naphthalene in mice. The lack of major differences in the catalytic activity or enantioselectivity of putative detoxication enzymes (epoxide hydrolase or glutathione transferases) between mouse and hamster tissue, combined with data showing that the differences in the metabolic fate of naphthalene oxide in proximal versus distal airways are not dramatic, suggests that the initial epoxidation of naphthalene is an important factor in site-selective toxicity. These studies support the need to use tissue from defined airway levels for studies on the relationship of biochemical and metabolic factors important in cellular injury by lung toxicants, such as naphthalene, where there are dramatic regional differences in susceptibility to injury within the respiratory system.

Animals↗
PubMed2005

Interactions between prostaglandin E(2), liver receptor homologue-1, and aromatase in breast cancer.

Local synthesis of estrogens within breast adipose tissue by cytochrome P450 aromatase contributes to the growth of postmenopausal breast cancers. One of the major stimulators of aromatase expression in breast is prostaglandin E(2) (PGE(2)) derived from tumorous epithelium and/or infiltrating macrophages. Recently, the orphan nuclear receptor, liver receptor homologue-1 (LRH-1), has also been shown to regulate aromatase expression in breast adipose tissue. We therefore examined the expression of, and correlations between, aromatase and LRH-1 mRNA in a panel of breast carcinoma tissues and adjacent adipose tissue. LRH-1 mRNA expression was low in normal breast tissue but markedly elevated in both breast carcinoma tissue and adipose tissue surrounding the tumor invasion (thereby paralleling aromatase expression). Laser capture microdissection localized the site of LRH-1 expression to tumor epithelial cells but not to intratumoral stromal cells. A strong correlation between LRH-1 and aromatase mRNA levels was observed in tumor-containing adipose tissue but not in tumor tissue. Ectopic expression of LRH-1 in primary human adipose stromal cells strongly activated endogenous aromatase mRNA expression and enzyme activity. Finally, treatment of adipose stromal cells with PGE(2) induced expression of both LRH-1 and aromatase. We suggest that PGE(2) derived from breast tumor tissue may increase aromatase expression in the surrounding adipose stroma in part by inducing LRH-1 in these cells. The roles of LRH-1 in breast cancer proliferation merit further study.

Adipose Tissue↗
PubMed1998

Microsatellite instability and loss of heterozygosity at DNA mismatch repair gene loci occurs during hepatic carcinogenesis.

DNA mismatch repair is an important mechanism involved in maintaining the fidelity of genomic DNA. Defective DNA mismatch repair is implicated in a variety of gastrointestinal and other tumors; however, its role in hepatocellular carcinoma (HCC) has not been assessed. Formalin-fixed, paraffin-embedded archival pathology tissues from 46 primary liver tumors were studied by microdissection and microsatellite analysis of extracted DNA to assess the degree of microsatellite instability, a marker of defective mismatch repair, and to determine the extent and timing of allelic loss of two DNA mismatch repair genes, human Mut S homologue-2 (hMSH2) and human Mut L homologue-1 (hMLH1), and the tumor suppressor genes adenomatous polyposis coli gene (APC), p53, and DPC4. Microsatellite instability was detected in 16 of the tumors (34.8%). Loss of heterozygosity at microsatellites linked to the DNA mismatch repair genes, hMSH2 and/or hMLH1, was found in 9 cases (19.6%), usually in association with microsatellite instability. Importantly, the pattern of allelic loss was uniform in 8 of these 9 tumors, suggesting that clonal loss had occurred. Moreover, loss at these loci also occurred in nonmalignant tissue adjacent to 4 of these tumors, where it was associated with marked allelic heterogeneity. There was relatively infrequent loss of APC, p53, or DPC4 loci that appeared unrelated to loss of hMSH2 or hMLH1 gene loci. Loss of heterozygosity at hMSH2 and/or hMLH1 gene loci, and the associated microsatellite instability in premalignant hepatic tissues suggests a possible causal role in hepatic carcinogenesis in a subset of hepatomas.

Chromosome Mapping↗
PubMed2006

Mitochondrial neurogastrointestinal encephalomyopathy: evidence of mitochondrial DNA depletion in the small intestine.

BACKGROUND & AIMS: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disease clinically defined by gastrointestinal dysmotility, cachexia, ptosis, ophthalmoparesis, peripheral neuropathy, white-matter changes in brain magnetic resonance imaging, and mitochondrial abnormalities. Loss-of-function mutations in thymidine phosphorylase gene induce pathologic accumulations of thymidine and deoxyuridine that in turn cause mitochondrial DNA (mtDNA) defects (depletion, multiple deletions, and point mutations). Our study is aimed to define the molecular basis of gastrointestinal dysmotility in a case of MNGIE. METHODS: By using laser capture microdissection techniques, we correlated histologic features with mtDNA abnormalities in different tissue components of the gastrointestinal wall in a MNGIE patient and ten controls. RESULTS: The patient's small intestine showed marked atrophy and mitochondrial proliferation of the external layer of muscularis propria. Genetic analysis revealed selective depletion of mtDNA in the small intestine compared with esophagus, stomach, and colon, and microdissection analysis revealed that mtDNA depletion was confined to the external layer of muscularis propria. Multiple deletions were detected in the upper esophagus and skeletal muscle. Site-specific somatic point mutations were detected only at low abundance both in the muscle and nervous tissue of the gastrointestinal tract. Analysis of the gastrointestinal tract from 10 controls revealed a non-homogeneous distribution of mtDNA content; the small intestine had the lowest levels of mtDNA. CONCLUSION: Atrophy, mitochondrial proliferation, and mtDNA depletion in the external layer of muscularis propria of small intestine indicate that visceral myopathy is responsible for gastrointestinal dysmotility in this MNGIE patient.

Adult↗
PubMed2005

Clinicopathological and molecular genetic analysis of HNPCC in China.

AIM: To explore the clinicopathological and molecular genetic features of hereditary nonpolyposis colorectal cancer (HNPCC) in Chinese population. METHODS: We collected 16 Chinese HNPCC families from Wenzhou, Zhejiang Province, China. Tumor tissues and peripheral white blood cells were studied using microdissection, microsatellite analysis, immunostaining of hMSH2 and hMLH1 proteins and direct DNA sequencing of hMSH2 and hMLH1 genes. RESULTS: (1) A total of 50 patients had CRC. Average age at diagnosis of the first CRC was 45.7 years; 40.9% and 28.7% of the CRCs were located proximal to the splenic flexure and in the rectum, respectively. Thirty-eight percent of the colorectal cancer patients had synchronous and metachronous CRC. 34.4% and 25% of the CRCs were poor differentiation cancer and mucinous adenocarcinoma, respectively. Fourteen extracoloni tumors were found, and the hepatic cancer was the most common tumor type. Twenty-one patients whose median survival time was 5.7 years died during 1-23 years. Twenty-nine patients have survived for 1-28 years, 58.6%, 41.4% and 24.1% patients have survived for more than 5, 10 and 15 years, respectively; (2) All nine tumor-tissues showed microsatellite instability (MSI) at more than two loci. Four tumor-tissues lost hMSH2 protein expression and one lost hMLH1 protein expression. Three pathological germline mutations were identified from five genetically analyzed families; two of three mutations had not been reported previously as they were a transition from C to A in exon 14 (codon 743) of hMSH2 and a TTC deletion in exon 14 (codon 530) of hMLH1. CONCLUSION: Chinese HNPCC have specific clinicopathological features, such as early onset, propensity to involve the proximal colon, and high frequency of multiple CRCs, liver cancer more frequent than endometrial cancer. Chinese HNPCC showed relatively frequent germline mutation of mismatch repair (MMR) genes that correlated closely with high-level MSI and loss of expression of MMR genes protein.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Correlation of emmprin expression in vascular endothelial cells with blood-brain-barrier function: a study using magnetic resonance imaging enhanced by Gd-DTPA and immunohistochemistry in brain tumors.

In a previous study, we demonstrated that the expression levels in tumor cells of emmprin (CD147) correlated with the grade of astrocytic tumors. Also, we found that emmprin was expressed in vascular endothelial cells of the non-neoplastic brain and hypothesized that emmprin expression could be associated with normal blood-brain-barrier (BBB) function of vascular endothelial cells. In this study, this possibility was examined in non-neoplastic brain, glioma and metastatic carcinoma tissues by comparing emmprin immunohistochemistry with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) enhancement of magnetic resonance imaging (MRI), which is a clinical indicator of the BBB function. This study included 10 cases of non-neoplastic brain tissues, 7 of metastatic carcinoma, 7 of diffuse astrocytoma, 4 of anaplastic astrocytoma and 13 of glioblastoma multiforme. In all the cases, MRI with administration of Gd-DTPA was performed. The lesions were resected using the microdissection method with the help of ultrasonography and a neuronavigator. The tissues from Gd-DTPA-enhanced or non-enhanced areas were processed into frozen sections and subjected to immunohistochemistry with anti-emmprin antibody. The expression of emmprin in brain vascular endothelial cells inversely correlated with Gd-DTPA-enhancement of MRI: emmprin was positive in tissues not enhanced by Gd-DTPA and was negative in DTPA-enhanced tissues. Since BBB function presumably remains unimpaired in regions in which MR images are not Gd-DTPA-enhanced, emmprin expression appears to be associated with unimpaired BBB function. This is the first report to demonstrate a possible correlation between emmprin expression and BBB function in humans.

Adult↗
PubMed2006

Global proteomic analysis of microdissected cirrhotic nodules reveals significant biomarkers associated with clonal expansion.

Cirrhosis is a heterogeneous tissue composed of polyclonal regenerative and monoclonal neoplastic, potentially malignant nodules from which hepatocellular carcinoma (HCC) might develop. The aim of this study was to investigate proteomic profile changes associated with clonal expansion of cirrhotic nodules and malignant transformation of monoclonal nodules. Seventy-one cirrhotic nodules from 10 female patients with six HCC were dissected from liver surgical specimen by laser capture microdissection. Clonal status of each nodule was assessed by the study of X-chromosome inactivation pattern using the human androgen receptor. Protein profiles were determined by surface-enhanced laser desorption ionisation-time-of-flight technology using Q10 arrays (Cyphergen ProteinChip). Molecular weight of differentially expressed protein peaks was assessed. An average of 50 protein peaks was obtained for each nodule's profile. Comparison of protein profiles in polyclonal (n=45) and monoclonal cirrhotic nodules (n=26) identified three differentially expressed protein peaks (10,092, 54,025 and 62,133 Da). All were upregulated in monoclonal nodules. Twelve peaks were differentially expressed between monoclonal nodules and HCC with nine proteins upregulated in cancer samples. This study confirms that proteome analysis can be achieved from a limited number of microdissected cells, and provides further insight into the process of clonal expansion and malignant transformation of cirrhotic nodules.

Adult↗
PubMed1998

Morphologic diversity in malignant melanoma: the potential use of microdissection and the polymerase chain reaction for diagnosis.

Malignant melanoma (MM) can mimic soft tissue (ST) and epithelial neoplasms. An immunoperoxidase (IP) panel and a morphologic comparison of the primary are used in diagnosis, which can be difficult when the morphologic and IP profiles of a metastatic lesion simulate those of an ST neoplasm. Through the comparison of known genetic abnormalities in primary and metastatic neoplasms, a definitive diagnosis can be suggested on the basis of the finding of identical allelic losses through the use of microdissection (MD) and the polymerase chain reaction (PCR). Genetic alterations involving the p16 gene on chromosome 9p21 have been observed in MM. We present the case of a 56-year-old man with known MM in whom multiple metastatic lesions to the skin and an adrenal gland developed during a 5-year period. A fine-needle aspiration (FNA) of a new ST buttock lesion was performed; the specimen had cytologic features different from those of the primary neoplasm and simulated a possible primary ST neoplasm. We attempted to make a definitive diagnosis of MM in the FNA of the ST buttock lesion through a genetic comparison with the primary neoplasm as well as with the other metastatic sites. Direct-visualization MD was performed on histologic glass slides of the primary and adjacent tissue (normal control), and the metastatic lesions, along with malignant cell clusters from the buttock lesion FNA. DNA was extracted and PCR amplified with primers D9S171 and IFNA for the p16 locus at the 9p21-22 region. Loss of heterozygosity for the D9S171 marker at the p16 gene locus was identified in all of the neoplastic tissue tested. Normal skin elements did not show deletion. The combination of MD and PCR are powerful tools that can be used for the comparison of genetic abnormalities in primary and metastatic neoplasms with unusual morphologic features to help support a diagnosis with a noncontributory IP.

Adrenal Gland Neoplasms↗
PubMed2000

Diagnosis of papillary thyroid carcinoma is facilitated by using an RT-PCR approach on laser-microdissected archival material to detect RET oncogene activation.

OBJECTIVE: The purpose of this study was to investigate the value of the expression of the RET oncogene (rearranged during transfection) in papillary thyroid carcinomas (PTC) and its variants in the differential diagnosis of thyroid neoplasias. According to the literature RET oncogene activation by chromosomal rearrangements has been exclusively implicated in PTCs. METHODS: To establish the incidence of RET activation in PTCs we used 5- to 10-microm sections from archival paraffin blocks. Either parts of the tissue slices were manually dissected or a few distinct cells were microdissected by laser-mediated manipulation with the Robot-MicroBeam system. RNA was extracted from paraffin-embedded thyroid tumors and the corresponding normal tissue. RT and nested PCR were performed using primers for RET/PTC1, PTC2 and PTC3, or for RET exons 12 and 13. PCR products were resolved by gel electrophoresis. RESULTS: We detected RET transcription in approximately 85% of the PTCs including follicular variants and in isolated cells of the same tissues, but not in nonmalignant thyroid tissue. CONCLUSIONS: Our method may serve as an additional diagnostic tool to characterize ambiguous neoplasias and to identify especially nonpapillary, i.e. follicular tumors, as papillary carcinomas. Additionally, this study has demonstrated that expressed genes can be analyzed from routine histopathological tissue slides or pooled single cells. Large retrospective studies can also be performed with this method.

Adult↗
PubMed2004

Reepithelialization of a full-thickness burn from stem cells of hair follicles micrografted into a tissue-engineered dermal template (Integra).

We report a head and neck full-thickness burn injury that was reconstructed with a tissue-engineered dermal template and then early implantation of microdissected hair follicles through the silicone epidermis 12 days after the burn injury. The treatment resulted in complete reepithelialization and a hair-bearing scalp without the need for a split-thickness skin graft. Restoration of the stem cell population, hair growth, and earlier reepithelialization were achieved using this novel micrografting technique, and histologic examination confirmed maturation of a normal skin type over the subsequent 2 years.

Adult↗
PubMed2006

Expression status of RUNX1/AML1 in normal gastric epithelium and its mutational analysis in microdissected gastric cancer cells.

Although Runt-related transcription factors RUNXs (RUNX1-3) have a high similarity in their structure, only RUNX3 is known to be involved in gastric carcinogenesis. First, we examined mRNA expression of these three RUNX genes in the gastric mucosa, and, finding only RUNX2 was not expressed there, we further investigated RUNX1 and RUNX3 expression in three regions including the pit, isthmus/neck, and gland regions of the human normal stomach and whether RUNX1 is involved in gastric carcinogenesis. The mRNA expression of RUNX1 and RUNX3 was examined by use of the three regions isolated by laser-captured microdissection (LCM) and by use of primary gastric cancer tissues. Furthermore, RUNX1 mutational analysis was performed in the cancer cells, which also were isolated from 44 paraffin-embedded gastric cancer tissues by LCM. RUNX1 was co-expressed with RUNX3 in the pit region, and has cell growth-inhibition activity similar to RUNX3. RUNX3 has been reported to be suppressed by DNA methylation in a subset of gastric cancers; however, the expression of RUNX1 mRNA was observed in all of the gastric cancer cell lines and gastric cancer tissues that we examined. No RUNX1 mutation was found in the 44 gastric cancer patients. Although RUNX1 is similar to RUNX3 in both the expression pattern in the stomach and its cell growth-inhibition activity, RUNX1 is not involved in most cases of gastric cancers. These results suggest that the transcriptional target genes are different between these two family genes.

Cell Differentiation↗
PubMed2002

Differential gene expression in breast cancer cell lines and stroma-tumor differences in microdissected breast cancer biopsies revealed by display array analysis.

To examine gene-expression patterning in late-stage breast cancer biopsies, we used a microdissection technique to separate tumor from the surrounding breast tissue or stroma. A DD-PCR protocol was then used to amplify expressed products, which were resolved using PAGE and used as probe to hybridize with representative human arrays and cDNA libraries. The probe derived from the tumor-stroma comparison was hybridized with a gene array and an arrayed cDNA library derived from a GCT of bone; 21 known genes or expressed sequence tags were detected, of which 17 showed differential expression. These included factors associated with epithelial to mesenchymal transition (vimentin), the cargo selection protein (TIP47) and the signal transducer and activator of transcription (STAT3). Northern blot analysis was used to confirm those genes also expressed by representative breast cancer cell lines. Notably, 6 genes of unknown function were restricted to tumor while the majority of stroma-associated genes were known. When applied to transformed breast cancer cell lines (MDA-MB-435 and T47D) that are known to have different metastatic potential, DD array analysis revealed a further 20 genes; 17 of these genes showed differential expression. Use of microdissection and the DD-PCR array protocol allowed us to identify factors whose localized expression within the breast may play a role in abnormal breast development or breast carcinogenesis.

Biomarkers, Tumor↗
PubMed1989

Quantitative distribution of nuclear androgen receptors in microdissected areas of the rat brain.

The binding of androgens to specific high-affinity receptor sites in brain tissue is postulated as an initial event in the mechanism of central androgenic action. In an effort to assess the functional capacity of the androgen receptor system in the central nervous system, we measured the concentration of nuclear (ARn) as well as cytosolic androgen receptors (ARc) in 13 microdissected brain samples from intact male and female Sprague-Dawley rats. Tissues from 6 rats were combined for each determination and androgen receptor contents were measured with single-point in vitro assays that used saturating concentrations of high specific activity 3[H]dihydrotestosterone. We found that ARc levels tended to be higher in females than males although the general patterns of distribution were very similar. As expected, ARn concentrations were significantly higher in males than females. The highest concentrations of ARn (greater than 100 fmol/mg DNA) in males were measured in the ventromedial nucleus of the hypothalamus and medial amygdala; intermediate levels (50-100 fmol/mg DNA) were found in arcuate nucleus-median eminence, medial preoptic nucleus, periventricular preoptic area, bed nucleus of the stria terminalis, anterior hypothalamus, periventricular anterior hypothalamus, lateral septum, and parietal cortex, and low levels (less than 50 fmol/mg DNA) were measured in lateral preoptic nucleus and cortical amygdala. With the exception of the periventricular preoptic area (74 +/- 33 fmol/mg DNA), only very low concentrations of ARn were measured in females. These data provide the first quantitative profile of ARn in discrete brain nuclei and subregions of the rat.

Animals↗
PubMed1995

A microdissection approach to detect molecular markers during progression of prostate cancer.

To investigate the underlying mechanisms of carcinogenesis, we have developed a technique to determine the frequency of genetic changes in prostatic carcinoma tissue. We have demonstrated that at a ratio of between 1:4 and 1:9 mutant-normal alleles, the signal from a mutant TP53 allele is not apparent after polymerase chain reaction (PCR) amplification and further direct sequencing or single-strand conformation polymorphism (SSCP) analysis. To bypass this problem, which is inherent in the heterogeneity of the prostate tissue and of the tumour, we selected areas of graded prostate tumours (Gleason score) from cryosectioned preparations and microdissected these cells (20-100 cells). After anionic resin removal of proteins, PCR amplification of TP53 gene exons 5/6 and SSCP analysis, an abnormal SSCP band shift was observed in suspected tumour cells, compared with microdissected stromal cells used as an internal control, while (1) a crude preparation of tissue DNA carrying the tumour did not show any abnormality and (2) immunostaining by a set of monoclonal antibodies against TP53 protein remained negative. Nucleotide sequence analysis of the different bands confirmed the presence of a mutation in the TP53 gene exon 6 position 13,336 in an abnormal band for one specimen, while no mutation was detected in the normal SSCP band. By targeting recognised tumour cells we can find DNA mutations which are undetectable using the standard technique of whole-tissue DNA extraction, particularly in a heterogeneous tumour such as carcinoma of the prostate.

Base Sequence↗
PubMed2006

Cell-specific gene expression in patients with usual interstitial pneumonia.

RATIONALE: Usual interstitial pneumonia (UIP) is characterized by extracellular matrix deposition and the development of pulmonary fibrosis. Fibroblastic foci found in the lung are believed to represent an early stage in the evolution of this disease. OBJECTIVES: To compare gene expression profiles in different components of lung tissue (fibroblastic foci, adjacent epithelium, and areas of type 2 pneumocyte hyperplasia) from patients with UIP, and contrast these profiles to distal, uninvolved (control) alveolar tissue from patients undergoing lung resection for cancer. METHODS: Lung resection tissue (UIP, n = 11; controls, n = 11) was snap-frozen for subsequent laser capture microdissection, followed by mRNA extraction, linear amplification, and quantitative real-time polymerase chain reaction. RESULTS: In patients with UIP, tissue inhibitor of matrix metalloprotease-1 and matrix metalloprotease (MMP)-2 gene expression was up-regulated within the fibroblastic foci compared with the overlying epithelium (p = 0.03, p = 0.02), and to control alveoli (p = 0.001, p = 0.04), respectively. MMP-9 and MMP-7, as well as osteopontin, were up-regulated in fibroblastic foci (p = 0.01, p = 0.08, p = 0.08), the adjacent epithelium (p = 0.001, p = 0.001, p = 0.03), and the hyperplastic type 2 pneumocytes (p = 0.02, p = 0.001, p = 0.08), respectively, compared with control alveoli. CONCLUSION: Altered gene expression of important profibrotic mediators in the different cellular lung compartments in patients with UIP likely plays an important role in pathogenesis of the deranged extracellular matrix deposition and subsequent fibrosis in this condition.

Aged↗
PubMed2003

[Manual microdissection of defined cells and RNA extraction for gene expression analysis of esophageal carcinoma progress].

OBJECTIVES: To isolate cells of interest from heterogeneous tissue blocks to obtain accurate representations of molecular alterations acquired by neoplastic cells so as to meet the demands of further study on gene expression patterns of the esophageal carcinoma (EC) evolution. METHODS: Blocks of EC were stored at -70 degrees C as close as possible to the time of surgical resection. The tissue block was embedded in OCT and frozen sections of 35 microns in thickness were cut in a cryostat under strict RNAse-free conditions. Individual frozen sections were mounted on plain glass slides and 30-gauge needle attached to a 1 ml syringe was used to microdissect defined cells in the sections. The procured cells were used for total RNA extraction. RESULTS: An optimized protocol of manual microdissection was developed successfully whereby regions with an area as small as 1/25 mm2 could be accurately dissected. The RNA recovered from procured cells was of high quality suitable for subsequent applications of molecular analysis as assessed of 18S and 28S rRNAs by electrophoresis on agarose gel. CONCLUSIONS: It is believed that manual microdissection is capable to procure defined cell populations from complex primary tissues, thus allowing investigation of tissue-, cell-, and function-specific gene expression patterns. The technique is simple, easy to perform, versatile, and of particular usefulness when laser capture microdissection (LCM) is practically unavailable.

Cell Separation↗
PubMed2004

Evaluation of p53 mutations in premalignant esophageal lesions and esophageal adenocarcinoma using laser capture microdissection.

p53 mutations have been implicated in the development of esophageal malignancies. The purpose of this study was to assess more accurately the incidence and types of p53 mutations in Barrett's esophagus (BE) with and without dysplasia and in esophageal adenocarcinoma, using pure preparations of epithelial cells obtained by laser capture microdissection (LCM). Assays were performed on paraffin-embedded tissue samples of normal antrum and premalignant and malignant esophageal samples from 57 patients, including 16 controls, 10 with BE metaplasia alone, 20 with BE-associated dysplasia, and 11 with BE-associated adenocarcinoma. All tissues were processed for LCM. DNA was extracted from isolated cells, and polymerase chain reaction (PCR) was performed using oligonucleutide primers for exons 5-8 of p53. PCR products were processed for DNA sequencing. p53 sequence abnormalities were identified in 2/16 cases of normal antrum and regenerative/chemical gastritis, 1/10 cases of BE, 1/20 cases of BE with dysplasia, and 2/11 cases of adenocarcinomas. The abnormalities occurred in exons 7 and 8 in the form of point mutations. Our results, using LCM, show that p53 gene mutations are relatively rare in esophageal preneoplastic and neoplastic conditions. Only point mutations were detected, but no deletions/insertions were identified.

Adenocarcinoma↗
PubMed2005

Analysis of hematopoietic development during human embryonic ontogenesis.

We describe here diverse methods used to study the onset of hematopoiesis in the human embryo and fetus. In the first part of this chapter, the criteria for estimating developmental stages in human embryos are discussed. This section also presents in detail a refined method for embedding and freezing intact human embryonic tissues that are destined to be analyzed by histology and immunostaining. In the second section, several protocols for the microdissection of human embryos are described in detail, with special attention given to differences encountered between tissues at different ages of gestation. Because of the limited number of cells available at the early stages of human gestation, we have established a miniaturized cell amplification system permitting further development of intact organ rudiments dissected from a human embryo and cultured in toto. The last part of the chapter is devoted to the study of myeloid and lymphoid potentials using, respectively, a mouse bone marrow-derived stromal cell line and cultured mouse embryonic thymus rudiments.

Cell Differentiation↗